Breaking in a cam

Scared Flat Breaking in a Cam

Tom Keyes; Redding, CA: I am going to start my next project this summer: a ’32 DeSoto three-window coupe with a ’56 first-gen 354 Hemi, a four-speed trans, a Heidts IFS, and a Jag IRS. After reading your article on breaking in a flat-tappet cam (Aug. ’11), I have some questions. I’ve been in the hot rod hobby for more than 45 years and have never had a problem breaking in a cam before, so you scared me! My motor will have 10:1 forged pistons, mildly ported stock heads, a Hot Heads 2x4 tunnel-ram manifold, zoomie street headers with baffles, and a Hot Heads hydraulic flat-tappet cam rated at 0.485-inch lift and 280 degrees duration. Horsepower will be in the 350 to 400 range. Your article says there is a problem with today’s modern oils and “cam lobe failures in engines running aggressive flat-tappet hydraulic camshafts.” Just what is considered an “aggressive” hydraulic camshaft? The way I read the article, I assume only hydraulic cams have this problem, as you refer to hydraulic cams, not solid lifter cams. Is this the case, and if so, why? And about additives, do I just add a can or bottle to SM- or SN-rated oils with each oil change after the first 100 miles on the break-in oil? Thanks for your advice.

CC Quickies
Homecoming

While in Santa Barbara shooting pictures of Christian France’s Coyote Fox, Staffer John McGann stopped by the Santa Barbara County Sheriffs’ Department headquarters for this photo op. The mechanics in the county garage were interested in the car’s transformation in the years since it left their care. A couple of the deputies asked if John could do the same to their cars, too.

Breaking in a camJeff Smith: When I first read your letter, Tom, I thought, Wow, I didn’t mean to scare anybody. But then it occurred to me that perhaps a little fear is a good thing, because it increases awareness of a potential problem. You bring up some excellent points that were not included in the story. Most important, the lubrication issue both from breaking in a cam and continuous-use standpoint is applicable to any flat- tappet camshaft/lifter system. What we’re talking about is what engineers call a sliding follower, as opposed to a roller follower like a roller lifter. It makes sense that sliding followers or flat-tappet cams create significantly greater sheer and heat, especially when additional load is created. This additional load comes from higher valvespring pressures used in a performance engine. Before 1993, the levels of phosphorous and zinc (commonly referred to as ZDDP) were unregulated and were in the range of 1,800 parts per million (ppm). With the American Petroleum Institute (API) SM in 2006 and the current SN standard, the maximum phosphorous was reduced first to 850 ppm and now to 800 ppm. API testing of stock, production, flat-tappet engines saw no significant wear problems, but these test engines used both very mild cam lobe profiles and (more important) very conservative (weak) valvespring pressures.

The problem with the API SM oil is that it clearly won’t stand up to an “aggressive” cam design and requires higher spring pressures. I used this term only because it is a difficult area to define. But let’s just say if you are using even a mild street cam with only 10 or 20 percent higher-than-stock spring pressures, the engine is entering a potential problem area–even after a successful break-in procedure. Let’s use some basic numbers. A stock small-block Chevy flat-tappet cam uses seat (valve closed) spring pressures of between 80 and 90 pounds with open pressure of roughly 250 pounds. At these loads, current API SN engine oil has sufficient ZDDP levels to prevent excessive wear. I’ve been using SM oil in my flat-tappet camshaft ’93 350ci GMC pickup for the last five years without a problem. The engine now has more than 120,000 miles and runs as well as it did when I first purchased it, but if I were to measure the valvespring load on the seat (valve closed), I doubt there would be more than 75 pounds of load. A strong performance cam can see an increase in seat pressure to 110 pounds and open pressure of maybe 300 pounds. Plus, a performance cam lobe is designed to quickly accelerate the lifter and generate more lift. This reduces the total contact area between the lobe and the lifter. This reduction in the contact area means the load increases dramatically. Phosphorous and zinc are high-pressure, antiwear lubricants. These additives are self- sacrificing, which means over time the additives are depleted. One reason oil needs to be changed is so these additives can be replaced. During our research, we found an additive product called ZDDPlus (ZDDPlus.com). The ZDDPlus product is a small, 4-ounce bottle of concentrated zinc and phosphorous designed to be used with between 4 and 6 quarts of off-the-shelf SM or SN engine oil that will raise the phosphorous level of the engine oil to pre-2004 levels. On the company’s website, we found several technical papers, one of which showed the results of an independent test with an engine that began with a phosphorous level of 1,800 ppm. After the equivalent of 2,000 miles of street driving, the phosphorous level dropped to roughly 600 ppm. While the results could be different for other engines, it’s clear the trend is that even after just 1,000 miles of driving, the levels had dropped by more than 50 percent. This information was found in ZDDPlus’ Tech Brief Number 8 on page 3.

One area I didn’t get into with the story (because it was becoming too long!) was oil additives. The oil companies tell you that you should not add anything to their oil because of possible “additive clash” issues. However, in the case of the ZDD additive, it appears you are merely doing what the oil companies used to do before the change to the API SM standard. This will probably draw criticism from oil chemists, but I sense that even a poorly blended additive is better than nothing. ZDDPlus claims it is completely compatible with all current SM/SN-base stock oils, including synthetics. On ZDDPlus.com, you will find an absolute treasure trove of technical papers that might take the better part of a day to read and digest. I’ve read barely half the papers and am impressed with the research that went into the presentations. The cost of one bottle of ZDDPlus is around $10, which, for a 5-quart oil change, just about doubles the cost of the oil from $10 ($2 each) to $20.00, but this is really cheap insurance, and you don’t have to chase around for boutique or race oil from mail-order houses, where it can cost $5 or more per quart along with a shipping charge. There is a lot more to this story if you really want to get into some technical information about oil, viscosity, base stocks, oil testing, and much more. It’s also important to reiterate that ZDDPlus is intended for vehicles without catalytic converters, as high-zinc and phosphorous levels in the oil will contribute to contaminating a catalytic converter.

So to alleviate your fears about running a flat-tappet camshaft and prevent you from chasing after a hydraulic roller application just for lubrication reasons, I’d say once you have successfully broken in your flat-tappet camshaft by using a high-quality break-in oil from one of the companies we tested in our story, you could use an off-the-shelf API SN oil along with a bottle of ZDDPlus and more than likely your engine will be protected with sufficient levels of zinc and phosphorous. This is not the only solution, but it appears to be one of the most cost efficient.

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A Question of Balance

Craig Wilhelm; Powhatan, VA: I have a ’95 Formula Firebird with a 383 LT1. I used a 6-inch rod kit from Eagle (PN B13057L030). This was an internal balance stroker kit with a cast crank and forged Mahle pistons. The cam is the GMPP LT4 Hot hydraulic roller with Comp Cams High Energy hydraulic rollers and GMPP 1.6 rockers. I also used an ATI Super Damper with the ATI hub. When stock, these engines are neutral balanced in the front and externally balanced in the rear. I had my machine shop assemble the short-block and do all the clearances and balancing because I was in a time crunch to get the car done. I asked the machine shop if they could balance the stock flywheel to the rotator kit. They said they could, so I went with it.

The problem is that the engine vibrates from idle through about 4,000 rpm. While idling, the engine seems to oscillate up and down. Could it be possible that it’s not balanced correctly? While assembling the engine, I didn’t really notice any machine marks on either the flywheel or the crank. I have known these guys for years and they are one of the area’s best machine shops, and I trusted them. When I put the flywheel on the crank, I had to de-burr it with a flapper wheel so it would fit the rear of the crank. I would think that had they balanced it, they would have corrected that when they did the work. I know I indexed the flywheel to the crank correctly because I lined up the dowel holes. The dowel, however, was missing, so I left it out. Could that be it?

I suspect the flywheel wasn’t balanced at all. I want to either get the flywheel neutral balanced or buy a new zero-balance flywheel. Your suggestions and thoughts would be greatly appreciated.

CC Quickies
Engine Swap

Guess what car this Viper engine resides in? Email your response to CarCraft@CarCraft.com. We’ll reveal more about this cool program in a couple of months.

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Jeff Smith: In 1986, Chevy changed the traditional small-block engine from the two-piece rear main seal to the one-piece style. The original two-piece rear main seal crankshaft flange used a small weight on the end of the crank. Adopting the one-piece rear main seal required moving the offset weight into the flywheel or flexplate, setting up an odd combination in which the harmonic balancer is still a neutral-balance unit, while the flywheel (or flexplate) still required offset weight. With the Eagle stroker packages, balance depends on the crank you order. Eagle’s forged cranks are designed as true “internal/internal,” which means the balance is all handled within the rotating assembly, and the engine requires a neutral balancer and a flywheel/flexplate. Eagle’s cast-crank stroker combinations are packaged both ways—you can get either a true internally balanced package or one that requires using a neutral harmonic balancer and an offset weight flywheel/flexplate. We called Eagle to verify the cast-crank stroker package you used. Eagle told us your package is internal/internal, which means it requires a harmonic balancer and flywheel/flexplate with a neutral balance. The stock LT1 flywheel you are using is an external-balance design with a weight offset and is therefore your vibration smoking gun. What is unclear is how your balance shop overlooked this fact. One clue that leads us to believe they missed this critical point is your observation that it looked as if they never bolted the flywheel onto the crankshaft. If the crank assembly was balanced separately from the flywheel at a different time, it’s possible they may not have made the connection that the flywheel should be neutral balanced. An offset weight flywheel will usually have holes drilled into the flywheel instead of an added offset weight. Flexplates typically have external weight welded to the face. Assuming your flywheel has the drilled holes, it will need to be neutral balanced. We’re betting that offset weight in the flywheel is the problem.

Looking into this a little further, we spoke with Danny O’Donnell at West Valley Balancing in Chatsworth, California, who has years of experience with engine balancing. He says the best way to balance an engine is to include the flywheel, clutch, and pressure plate together as a unit. He requires the customer to supply all the parts, including the fasteners. What many car crafters don’t realize is that older pressure plates require special shouldered, 3/8-inch NC bolts that not only attach the pressure plate but, more important, center it on the flywheel. If these shouldered bolts are not used, the pressure plate can move by as much as 0.030-0.040 inch, which is more than enough to create a vibration. Later-model vehicles use two or three small dowel pins to locate the pressure plate. This design does not require a shouldered bolt. If you think the wrong bolts may be the cause of your vibration, you could replace them with the proper fasteners (ARP and Mr. Gasket, for example) and start the engine with the pressure plate and clutch in place. You could also remove these components and start the engine with just the flywheel in place if the vibration persists. This would help isolate the problem.

3/8This is the crankshaft flange on a two-piece rear main seal small-block Chevy. Notice the small offset weight on the flange. A one-piece rear main seal flange cannot place this weight on the flange, so the weight is moved to the flexplate/flywheel, in essence making it an externally balanced engine in the rear.

Danny also mentioned that he’s run across poor surfacing work on a flywheel, in which case the friction surface is not parallel to the crank flange. This creates a thicker side to the flywheel that will cause an imbalance. The quick way to check for this is to measure the flywheel thickness with a caliper in four places around the circumference and compare the readings. He says as little as 0.020 inch can cause a vibration. This is rare, as most machine shops are competent when it comes to surfacing flywheels

It might also be helpful to note that when Chevy changed to a one-piece rear main seal, the flywheel bolt pattern also changed. The earlier two-piece rear main seal neutral-balance flywheels and flexplates will not bolt up to the one-piece rear main seal crank. I mention this in case someone might consider swapping flywheels or flexplates between these engines. (Editor’s Note: Craig subsequently contacted us and said that the balance shop indeed missed the fact that the flywheel should have been neutral balanced. The shop neutral balanced the flywheel, and the problem has been rectified.)

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CC Quickies
Tire Smoke

Did we run enough burnout pictures in this issue? The correct answer is “no.” So here’s another version of Ford’s Coyote V8 destroying the Nittos on Christian France’s ’86 Mustang.

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Headers for a Rat

Pierce Peck; via CarCraft.com: I read your article “How to swap an LS engine into your Chevelle” (May ’08). What was the result of putting the Hooker headers on your Chevelle? Was your ground clearance improved? I currently have a ’67 with 2-inch-dropped spindles and am considering replacing the current AFR-headed 540ci big-block with an LS engine and would like to keep as much ground clearance as possible. I am experiencing similar problems with the current mill. It has a set of Hooker 2455 2-inch Competition headers in it and ground clearance is too low despite a 26-inch tall front tire. Second question: Would a set of 2- or 21/8-inch Super Competition (or some other brand) headers give me more ground clearance? These headers were also a very tight fit and required some massaging with a propane torch and hammer to clear the steering column.

5/8This is the Flowmaster ball flange conversion kit for a collector and exhaust pipe. You will need two of these kits, one for each header. The 3-inch collector diameter to a 21⁄2-inch exhaust is adapter is PN 15925 ($85.95 from Summit Racing), but there are several additional variations for various sizes.

Any help you can provide will be welcome. The LS project is likely a couple of years away, so making the current big block more streetable is my first concern.

CC Quickies
What Is That?

Shoot us an email at CarCraft@CarCraft.com with your best guess at what is going on in this picture. The winners get to read about it in an article scheduled to run in December’s issue. Coincidentally, so will the losers.

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Jeff Smith: To answer your first question, we haven’t taken the time to swap in the new headers. We tried to bolt in the Hooker headers, but they require Hooker engine mounts, which locate the engine back about 1 inch from its current position with Edelbrock’s headers and engine mounts. While this in itself isn’t difficult, moving the engine rearward also relocates the transmission, causing the slip yoke on the driveshaft to bottom out in the back of the transmission. We’d need a new driveshaft to fix that problem. Since this wasn’t a high priority at the time, we chose to live with the reduced ground clearance. We’ve also learned that Edelbrock has since dropped its entire exhaust line, so the headers and exhaust system are no longer in production, just in case you were considering buying that package. As a point of reference, Edelbrock used a ’68 to ’72 Chevelle for its prototype, which may partly explain why the header hangs down so far on the earlier models. We really can’t comment on the actual clearance, but we did measure the distance from the cylinder-head bolthole to the bottom of the collector on both sets of headers, and we found more than a 2-inch shorter distance with the Hooker headers, which would lead us to believe that the Hooker headers should fit much closer to the floorpan and allow more road clearance with a lower car.

7/8V-band clamps are more expensive but offer excellent sealing and require no gaskets. You have to weld them in place, but they are very space efficient.

As for your problems with big-block header clearance for your ’67 Chevelle, going with a larger header tube is only going to increase the clearance problems. With a given amount of room between the engine and the steering shaft, going from a 2-inch-diameter tube to 21/8 inches is only going to make things worse. But, we have an idea that might help you. I just shot a photo of a 540ci big-block Chevy for an upcoming Horsepower! spread. While I was looking at the engine, a friend of mine spotted a slick idea that car owner Rich Blakley used to improve the clearance to the steering shaft. He removed the shaft and set it up in a lathe and reduced the overall diameter slightly in two places to increase the clearance between the header tubes and steering. We would suggest keeping this undersize to a minimum to ensure the shaft does not break, but with power steering, the load to the box is reduced and should be plenty safe.

Big-block Chevelles have always been challenged by ground clearance, and larger tubes don’t help, but if there is more than 1 inch of room between the collector and the floor, there is certainly room to improve the ground clearance. One trick we learned from Mark Stielow is to first place the car on a hoist where you have access to the headers. Using a torch, carefully heat the header primary tubes just behind the collector, then use a long prybar to bend the collector upward. This involves finesse, so work carefully. Stielow says he’s used this method to improve ground clearance on his Pro Touring Camaros. Another possibility is to eliminate that large, three-bolt collector flange. It takes up room on both the floorpan and ground clearance sides. To replace it, you can go with a ball flange adapter kit from Flowmaster or use V-band clamps. The Flowmaster kit uses a spherical ball shape to seal the collector to the exhaust system and has to be welded to the collector. It attaches to the intermediate pipes with a two-bolt connector. These bolts are parallel with the floor, improving ground clearance over the traditional three-bolt collector flange. The best way to go is with a set of V-band clamps. These clamps have been successfully used in the turbocharger industry for years, and Afco makes a set in 3- or 31/2-inch diameter. The clamps use two stainless steel sealing surfaces that are held together with a band clamp. The sealing surfaces have flanges that must be welded to the collector and the exhaust pipe, but to install or remove them, just slip the band clamp over the two sealing flanges, tighten the nut, and you’re done. We used these V-band clamps on my Chevelle exhaust system at the mufflers and the collectors. It’s a quick way to remove the system; they take up very little room compared with a three-bolt flange system and have no gaskets to leak.

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Get Off the Couch

Kayleigh Fetherston; Harford County, MD: My father owns a ’68 Firebird. This car has been in our garage since I was 2 years old, and I will turn 16 this June. My father wants to get the car running again, but he never has time. The summer of my graduation in 2013, he wants to drive it cross-country from Maryland to California, as his gift to me. I’ve been into cars since I was a little girl. I don’t know how to get my father back into the garage so he can work on his (my) car.

CC Quickies

When was the last time you saw any Pro Street car with fender skirts? It sounds weird, but on this T-bird it works in an odd sort of way.

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Jeff Smith: It’s great to hear that you’re really into cars, Kayleigh, so let’s see if we can help you motivate your dad. You’ve already taken the first step by writing to what let’s hope is still his favorite magazine after he reads this! As a father back when my children were younger, it seemed like there were often other demands on my time that took me away from my kids. Now that they’ve grown and are living their own lives, I realize it would have been fun to spend more time with them. Since you share a great common interest, I suggest choosing a time when your dad is home and just going out to the garage by yourself and starting to do something. It doesn’t really matter what you do—it could be just cleaning the garage so you and your dad have a pleasant place to work. Don’t re-arrange anything—remember, this is Dad’s garage. You could remove any junk that might be lying on the car or around it, air up the tires, clean it inside and out, and generally get it ready to be worked on. Your presence in the garage without him should motivate him to at least come out to find out what you’re doing. If he does, don’t say you’re tired of waiting for him to get motivated. That’s a negative response. Make all your communication with him around the car a positive experience. Just say something like “I just thought it would be fun to come out here and start cleaning the car. It would be great if you wanted to help me. I have a lot of questions about what we should do first.” That probably sounds corny, so you can restate it anyway that sounds more like you.

If working out in the garage when he’s home doesn’t motivate or shame him into getting off the couch, don’t get frustrated. He might think this is just a one-time thing. Next, talk to your mom about when it would be a good time to bring up working on the car with your dad. What you’re doing is enrolling both your parents into this project. Don’t be disappointed if you don’t get a big enthusiastic response. You are embarking on a long-term project. You might ask if your mom will come out and help you. Then there would be the two of you out there in the garage. If nothing else, your dad will probably have to come out to the garage just because everybody else is occupying what is normally his space.

Consider all this an ongoing process. At various times, you can ask your dad if he has a plan about what things need to be repaired on the Firebird to make it roadworthy. Get him to talk about the car and what needs to be done. My wife has learned that if she needs me to do a major project, she begins the process a few days before by asking me about the best way to get it done. She’s getting me thinking about the project. With this approach, more than likely your dad will start thinking about the car at work or when he’s with his friends. Another subtle thing you can do is to begin the process of enrolling your dad’s car-guy friends into the project. This is a very powerful tool because they will be less subtle with your dad than you have to be. If you can enroll one of your dad’s best car-guy friends to come over and help you work on the car, your dad will be forced to be there. If nothing else, his buddies will shame him into it, but I don’t think it will have to go that far. I think that after just one fun session doing something that’s simple and easy on the Firebird, your dad will realize how much fun it is to work on the car with his daughter. Pretty soon he’ll look forward to having wrenches in his hands.

Of course, once you start this process, you must invest your time as well. This is not the time for you to go off to do something else and leave him there all alone. If you are going to plant the seed with the intent of driving this car across the country, it will take some effort and lots of hours out in the garage working on the car. Your dad knows that. But if the seed is planted and you continue to motivate him and honor and thank him for his efforts, this will keep him motivated. This is your secret weapon. Dads are huge on acknowledgement from their children, since they often feel as though their kids don’t really appreciate them. So, let’s say you’ve actually managed to motivate your dad out into the garage and he’s working on the car. Stay there with him, ask him questions about what he’s doing and why. Show him you really want to learn about his/your car and that you really care. Every once in a while, go in the kitchen and get him a soda or water or his favorite snack. These are little rewards that are subtle but very powerful. More than likely, this whole car rebuild will require major time and effort, so you two will be spending a lot of time together. Ask him about what he did in high school and the fun he had—maybe with this car. My guess is that this cross-country-drive idea was something he really wanted to do when he graduated from high school but never did. So now he’d like to share that dream with you. If you think about it, that’s pretty cool. All this will bring you closer together and if you make this whole process fun, your dad will actually look forward to getting out in the garage with you working on the car. Think of yourself as the cheerleader on the sidelines of the big football game. You dad is the quarterback of the team and every time he looks over at the sidelines, there’s his daughter cheering him on, believing in him. He’ll know what to do! If all this sounds like it goes way beyond just working on a really cool ’68 Firebird, then you’re absolutely correct.

Many years from now, you might look back on this as one of the best times you ever had with your dad. All this isn’t really about working on the car. That’s almost a side benefit. Strengthening the bonds that you already have with your dad will be of far greater importance than whatever occurs with the car.